Biodiesel: The Good and the Bad

By John O'Dell January 4, 2008


A field of canola yields oil that becomes biodiesel fuel.

By Mac Demere, Contributor

The fervor of biodiesel advocates, who range from sincere environmentalists to public relations professionals hired by multinational farming and commodity conglomerates, makes it easy to believe that this plant- and animal-derived alternative fuel is a near-magic solution to our energy needs.

Biodiesel promoters say it can do everything from ending our petroleum addiction to halting climate change. The words "ideal," "perfect" and "fantastic" are used frequently in discourse about the stuff.

Truth is that even with the puffery deflated there’s a lot to like about biodiesel.

Plusses abound

It is non-toxic, biodegradable, and meshes easily with current infrastructure.

It’s possible to use it in almost any diesel-engined vehicle and it also can be employed as home-heating oil.

Biodiesel reduces most tailpipe and greenhouse gas emissions and lessens our carbon footprint.

It's a better engine lubricant than the petroleum-based stuff, an advantage with the now-required ultra-low sulfur diesel fuel.

It’s safer to store and transport. It won’t ignite until about 300 degrees Fahrenheit, about twice the flash point of petro-diesel and about 345 degrees higher than gasoline, which can be ignited at 45 degrees below zero.

Unlike petroleum refineries, biodiesel distilleries can be constructed with little not-in-my-backyard opposition.

Some will say that its best attribute is that it eliminates the stink and smoke produced by conventional diesel fuel.

From algae to zoologicals

Biodiesel can be made from a vast array of plant oil and animal fat. Popular sources are soybeans, rapeseed, canola, sunflower seed, castor beans, coconuts and oil palm seeds. And, while no one is talking about using it for biodiesel, the opium poppy produces far more oil per acre than soybeans.

To reduce deforestation and crop shortages, researchers are experimenting with the likes of honge nuts from the pongamia tree, which grows freely along roads in India, and jatropha, which grows wild -- especially along railroad lines -- in most tropical areas. They’re also experimenting with algae, sawdust and sewage.

Used cooking oil and slaughterhouse leavings can also be turned into biodiesel.

All of the biodiesel feedstocks must go through an extensive refining process before the fuel can be used in vehicles. The oil, from plant or animal, is mixed with either ethanol or methanol and that mixture is then distilled and washed. The result is about 80 percent biodiesel.

Now the bad news

Remove all the spin and hype and it’s easy to conclude the biodiesel is an important part of the effort to reduce dependence on foreign petroleum and limit harmful emissions.

But there also are concerns that biofuels may to be similar to the 19th century medical practice of using morphine to cure alcoholism: The unintended consequences can be worse than the original problem.

For starters, hydrocarbon and nitrous oxide emissions actually increase when biodiesel is employed in the present generation of diesel engines. Emissions of sulfur, carbon monoxide and sooty particulates, however, are reduced.

Environmental disruption

In order to plant biofuel crops, farmers in the Dakotas and Montana have plowed up tens of thousands of acres of previously undisturbed native prairie grasslands, places that are among the most valuable nesting habitat for some duck species.

But that’s nothing compared to the millions of acres of Brazilian rainforest that is cut -- or burned -- down each year to clear land to grow, among other things, biofuel plants.

And in Southeast Asia, planting oil palms is the leading cause of rainforest destruction.

Meanwhile, grocery store prices rise as food crops are diverted to make fuel.

While growing plants suck carbon-dioxide out of the air, the emissions form producing and transporting biodiesel means that the net reduction in CO2 emissions is little more than 50 percent.

French fry oil not best

Some enthusiasts love biodiesel because it can be made relatively easily from used cooking oil – which would reduce the environmental impacts of growing plants specifically for fuel purposes.

But biodiesel from the French fry cooker at the local burger joint seems better suited for the hobbyist -- or for use as home heating oil -- than for use as a mass-market fuel.

For one thing, the quality of used fry oil varies radically, which would be a huge challenge for a large biodiesel producer.

Also, the so-called yellow grease biodiesel congeals into a Jell-O-like goop at between 40 and 65 degrees, so using it in most places requires a heated fuel tank or some other warming method.  And high-pressure diesel fuel injectors may not tolerate this thicker form of biodiesel – although there is on-going research aimed at resolving that issue.

Other problems for biodiesel include degradation of the fuel as it sits in storage tanks exposed to the sun; the likelihood of fuel-system choking microbial growth after six months of storage, and biodiesel's tendency to suck moisture out of the air and become fouled with water.

Can I use it in my car?

For many, the most important question is: "Can I run biodiesel in my vehicle?"

The answer is a very qualified “yes”.

If the biodiesel is made from virgin vegetable oil, comes out of a new storage tank, goes into a brand new vehicle and the ambient temperature doesn't fall below 10 degrees, you can easily run a B20 blend -- 20 percent biodiesel -- without a problem. In warmer climes, B50, B80 or even B100 may be possible.

But the answer becomes an unequivocal “no” if the biodiesel is pumped from a storage tank that previously held fossil-diesel.  And until development of anti-coagulation methods progresses, it’s also “no” if the biodiesel contains any animal fat or used cooking oil.

If you have a vehicle that previously ran on dino-diesel, you can safely convert to biodiesel only if you’re willing to do (or pay someone to do) a lot of work.

The reason: Biodiesel acts as a solvent on residue left behind by conventional diesel. The gunk that's loosened by biodiesel will clog oil filters and may ruin fuel pumps and injectors.

Filter, filter, filter

To use biodiesel in an older vehicle, begin by replacing all fuel filters. Next, ensure there’s a filter between the fuel tank and fuel pump, and one between fuel pump and fuel injectors. Then run a tank of B5 and replace the filters.

If the filters are loaded with goop, stay with B5 until the filters show little contamination. Then step up to B10 and check the filters. If the filters remain clean repeat with B15 and then B20.

Expect slightly worse fuel mileage and engine performance with biodiesel. It contains a bit less energy than a comparable amount of petroleum-based diesel: Motorists won’t notice a difference when running up to B20, but companies with large fleets of diesel vehicles that consume tens of thousands of gallons certainly will.

Growth is assured 

Good, bad or neutral, there will be a lot more biodiesel in our future.

It's not the magic bullet in our duel quest to end dependence on crude oil and find less polluting fuels for our vehicles, but, like many of the alternative fuels under development today, it is likely to be part of the solution.

Congress already has given biodiesel producers a $1 a gallon incentive.

And a bill has been introduced that would require the yearly use of biodiesel to increase from about 450 million gallons to 1.25 billion gallons by 2012.

That’s a small portion of the 60 billion gallons of petro-diesel used each year in the U.S.

But it's a start.


 Photo 1: Canola field, courtesy of Saskatchewan Department of Agriculture and Food

Photo 2: Palm seeds, courtsey of Australian Broadcasting Corp.

Photo Illustration: Green nozzle, courtsey of iStockphoto

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Click here to comment on this entry.
opfreak says: 6:12 PM, 01.07.08

learned a bunch from this article

SubyTrojan says: 11:30 AM, 01.08.08

Thanks, John! Mac's "article" was great! I'd love to meet him if he ever comes into our office sometime!

philip17 says: 2:47 PM, 01.09.08

Excellent and comprehensive article. I was bracing myself for the negatives and when I read them I was surprised to see that they were not problems with the fuel itself so much but with the manufacture of the fuel. It seemed that those problems could be overcome rather easily.
One point not mentioned, the conversion of crops to biodiesel is far more efficient than the conversion of corn to ethanol. Furthermore, the drop off in fuel efficienct between gas and ethanol is far greater than the drop off between petrodiesel and biodiesel.
By the way, a 2005 Jetta TDI has been added to the Edmunds Long Term Fleet. Eventually we will switch over to biodiesel and report fuel economy findings.

blackadder5639 says: 3:13 PM, 01.10.08

Great article! I was originally put off by it's length but enjoyed it once I started reading!

sirloin869 says: 5:46 AM, 08.27.11


still waiting on the zombie apokolypse


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